Safety bumpers for automatic guided vehicles that employ electric switching apparatus operable to stop the vehicle when the bumper is deflected are well known and are disclosed, for example, in U.S. Pat. Nos. 2,920,713, 3,496,317 and 3,1901,346. Also, in U.S. Pat. No. 3,664,701, a deflectable bumper for an automatic guided vehicle is employed wherein a reflective element on the vehicle bumper is adapted to reflect a light from a photocell to complete an electric circuit that permits the vehicle motor to operate and the vehicle brakes to be held in release position. When the bumper of this patented device strikes an obstruction, the bumper deflects causing the reflective element thereon to move out of alignment with the photocell carried by the vehicle to thereby interrupt the electric circuit, stopping the vehicle motor and applying the brakes. While this patented device operates adequately under most conditions, it occasionally presents problems since there are certain points on the bumper that do not activate the vehicle brakes when an obstruction is contacted because the bumper deflection is not adequate to move the reflector out of the beam of the photocell. Also, at times, up and down bumper movement, or wobble, when the vehicle is traversing uneven surfaces causes the reflector to move out of alignment with the photocell beam and results in false vehicle stops.
It is an object of the present invention to provide a reliable safety bumper for automatic guided vehicles that utilizes the advantageous features of the prior art devices while minimizing the disadvantages thereof.
It is a further object of the present invention to provide a reliable safety bumper for an automatic guided vehicle that deflects upon contact with an obstruction and causes interruption of an aligned light beam signal to a photocell to inactivate the vehicle motor and apply the vehicle brakes.
It is another object of the present invention to provide a reliable safety bumper for an automatic guided vehicle that minimizes false vehicle stops.